Ecological niche modeling of toxic dinoflagellate Prorocentrum cordatum in the Black Sea

Abstract The article deals with risk assessment of mass development of a toxic dinoflagellate species Prorocentrum cordatum (Prorocentrales, Dinophyceae) in various regions of the Black Sea by applying ecological niche modeling. Niche modeling was developed using the MaxEnt algorithm. The MaxEnt model training was based on the data of P. cordatum general distribution according to the GBIF source, along with the data on 8 environmental variables retrieved from the Bio-Oracle database. Quality evaluation of the obtained model was executed with the values of AUC statistics, and relative contribution of selected environmental variables to the model was also estimated. In order to additionally assess the applicability of the model, analyses of literature data (from 1886 through 2020) together with original data on the distribution of P. cordatum in the Black Sea (from 1986 to 2020) were carried out. Response curves of environmental variables with the highest permutation importance are given. Map projections of MaxEnt habitats suitability scores for P. cordatum in the Black Sea area are presented. According to our estimates, about 16 percents of the whole Black Sea area are in the high or very high risk zone of P. cordatum mass outbreaks. Maximum values of predicted suitability were obtained for the northwestern part of the Black Sea, while in other regions of the sea they coincided with location of large sources of anthropogenic eutrophication and further distribution of polluted waters by currents. The proposed mathematical model can be used to predict the appearance and mass development of other toxic species.